Nano-photonics or nano-optics is the study of the behavior of light on the nanometer scale. Near-field scanning optical microscopy (NSOM), photoassisted scanning tunnelling microscopy, and surface plasmon optics are examples of nano-optics technologies.
Recently nano-photonic semiconductor devices have been developed to have smaller dimensions than the wavelength of the lights emitted from the devices. Nano-photonic semiconductor devices may be used in various kinds of optoelectronic devices. There is current interest in improving the properties of optical confinement of nano-photonic semiconductor devices.